t520: Add better exception handling
t520: Add better exception handling

vogdb/cm,vogdb/cm,njam/CM,fauvel/CM,mariansollmann/CM,cargomedia/CM,fauvel/CM,cargomedia/CM,zazabe/cm,tomaszdurka/CM,fvovan/CM,mariansollmann/CM,fauvel/CM,njam/CM,tomaszdurka/CM,fauvel/CM,tomaszdurka/CM,tomaszdurka/CM,alexispeter/CM,cargomedia/CM,fvovan/CM,mariansollmann/CM,fvovan/CM,cargomedia/CM,fvovan/CM,christopheschwyzer/CM,njam/CM,njam/CM,vogdb/cm,tomaszdurka/CM,christopheschwyzer/CM,mariansollmann/CM,alexispeter/CM,alexispeter/CM,vogdb/cm,christopheschwyzer/CM,christopheschwyzer/CM,njam/CM,zazabe/cm,zazabe/cm,fauvel/CM,alexispeter/CM,zazabe/cm,vogdb/cm